For example, in an electrical inspection for a wafer on which a large number of integrated circuits are formed or a circuit device such as an electronic component, for example, a semiconductor device, there has been used a probe for an inspection which has inspection electrodes arranged in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected.
Conventionally, there has been used a probe for an inspection in which the inspection electrodes formed by a pin or a blade are arranged.
However, in the case in which the circuit to be inspected is a wafer having a large number of integrated circuits formed thereon, it is necessary to arrange a large number of inspection electrodes when fabricating a probe for an inspection to inspect the wafer. Therefore, the probe for an inspection is very expensive. Moreover, in the case in which the pitch of the electrodes to be inspected is small, it is hard to carry out the fabrication of the probe for an inspection itself.
Furthermore, a warpage is generally generated on the wafer and the state of the warpage is also varied for each product (wafer) For this reason, it is practically hard to cause each of the inspection electrodes of the probe for an inspection to come in contact with a large number of electrodes to be inspected in the wafer stably and reliably.
For the above reasons, in recent years, there has been proposed a probe for an inspection which serves to inspect an integrated circuit formed on a wafer, comprising a circuit board for an inspection on which a plurality of inspection electrodes is formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected on a surface, an anisotropically conductive sheet disposed on a surface of the circuit board for an inspection and a sheet-like probe in which a plurality of electrode structures extended to penetrate in a direction of a thickness thereof is arranged in a flexible insulating sheet (for example, see Patent Document 1).
FIG. 34 is an explanatory sectional view showing a structure according to an example of a conventional probe card comprising a circuit board 85 for an inspection, an anisotropically conductive sheet 80 and a sheet-like probe 90.
In the probe card, there is provided a circuit board 85 for an inspection having a large number of inspection electrodes 86 formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected over a surface, and a sheet-like probe 90 is disposed on the surface of the circuit board 85 for an inspection through the anisotropically conductive sheet 80.
The anisotropically conductive sheet 80 has a pressurizing conducting portion exhibiting a conductivity in only a direction of a thickness or exhibiting the conductivity in only the direction of the thickness when a pressurization is carried out in the direction of the thickness. There have been known the anisotropically conductive sheets having various structures. For example, Patent Document 2 and the like have disclosed an anisotropically conductive sheet obtained by uniformly dispersing a metal particle in an elastomer (which will be hereinafter referred to as a “dispersion type anisotropically conductive sheet”).
Moreover, Patent Document 3 and the like have disclosed an anisotropically conductive sheet obtained by unevenly distributing a conductive magnetic particle into an elastomer, thereby forming a large number of conductive portions extended in a direction of a thickness and an insulating portion for mutually insulating them (which will be hereinafter referred to as an “an uneven distribution type anisotropically conductive sheet”). Furthermore, Patent Document 4 and the like have disclosed the uneven distribution type anisotropically conductive sheet in which a step is formed between a surface of a conducting portion and an insulating portion.
The sheet-like probe 90 has a flexible insulating sheet 91 formed of a resin, for example, and has such a structure that a plurality of electrode structures 95 extended in a direction of a thickness is disposed on the insulating sheet 91 in accordance with a pattern corresponding to a pattern of electrodes to be inspected in a circuit device to be inspected.
Each of the electrode structures 95 has such a structure that a projected surface electrode portion 96 exposed from a surface of the insulating sheet 91 and a plate-shaped back electrode portion 97 exposed from a back of the insulating sheet 91 are integrally coupled through a short circuit portion 98 extended to penetrate through the insulating sheet 91 in a direction of a thickness thereof.
Such a sheet-like probe 90 is generally manufactured in the following manner.
First of all, a laminate material 90A obtained by forming a metal layer 92 over a surface of the insulating sheet 91 is prepared as shown in FIG. 35(a) and a through hole 98H penetrating in a direction of a thickness is formed on the insulating sheet 91 as shown in FIG. 35(b).
As shown in FIG. 35(c), subsequently, a resist film 93 is formed on the metal layer 92 of the insulating sheet 91, and furthermore, an electrolytic plating treatment is carried out by setting the metal layer 92 to be a common electrode. Consequently, the through hole 98H of the insulating sheet 91 is filled with a metal deposit so that the short circuit portion 98 coupled integrally with the metal layer 92 is formed, and furthermore, a projected surface electrode portion 96 coupled integrally with the short circuit portion 98 is formed on a surface of the insulating sheet 91.
Then, the resist film 93 is removed from the metal layer 92, and furthermore, as shown in FIG. 35(d), a resist film 94A is formed on the surface of the insulating sheet 91 including the surface electrode portion 96 and a resist film 94B is formed on the metal layer 92 in accordance with a pattern corresponding to a pattern of a back electrode portion to be formed, thereby carrying out an etching treatment over the metal layer 92. As shown in FIG. 35(e), consequently, an exposed portion in the metal layer 92 is removed so that the back electrode portion 97 is formed. Thus, the electrode structure 95 is formed.
Thereafter, the resist film 94A formed on the insulating sheet 91 and the surface electrode portion 96 is removed, and furthermore, the resist film 93 formed on the back electrode portion 97 is removed. Consequently, the sheet-like probe 90 is obtained.
In the probe for an inspection, the surface electrode portion 96 of the electrode structure 95 in the sheet-like probe 90 is provided so as to be positioned on an electrode to be inspected in the wafer over a surface of the wafer, for example, in the circuit device to be inspected.
In this state, the wafer is pressed by the probe for an inspection. Consequently, the anisotropically conductive sheet 80 is pressed by the back electrode portion 97 of the electrode structure 95 in the sheet-like probe 90.
Consequently, a conducting path is formed in a direction of a thickness between the back electrode portion 97 and the inspection electrode 86 of the circuit board 85 for an inspection over the anisotropically conductive sheet 80. As a result, an electrical connection between the electrode to be inspected in the wafer and the inspection electrode 86 of the circuit board 85 for an inspection can be achieved.
Then, a predetermined electrical inspection is executed for the wafer in this state.
According to such a probe for an inspection, the anisotropically conductive sheet 80 is deformed according to the degree of the warpage of the wafer when the wafer is pressed by the probe for an inspection. Therefore, it is possible to reliably achieve an excellent electrical connection for each of a large number of electrodes to be inspected in the wafer.
However, the probe for an inspection has the following problems.
In a process for forming the short circuit portion 98 and the surface electrode portion 96 in the method of manufacturing the sheet-like probe 90 described above, a plated layer formed by the electrolytic plating grows isotropically. As shown in FIG. 36, therefore, a distance W from a peripheral edge of the surface electrode portion 96 to that of the short circuit portion 98 is equivalent to a projection height h of the surface electrode portion 96 in the surface electrode portion 96 which is obtained.
Accordingly, a diameter R of the surface electrode portion 96 which is obtained exceeds a double of the projection height h and is considerably great.
For this reason, in the case in which the electrode to be inspected in the circuit device to be inspected is minute and is disposed at a very small pitch, a distance between the adjacent electrode structures 95 cannot be maintained sufficiently. As a result, in the sheet-like probe 90 which is obtained, the flexibility of the insulating sheet 91 is lost. For this reason, it is hard to achieve a stable electrical connection to the circuit device to be inspected.
In the electrolytic plating treatment, moreover, it is actually difficult to supply a current having an even current density distribution to the whole surface of the metal layer 92. Due to the uneven current density distribution, a growth speed of a plated layer is varied for each through hole 98H of the insulating sheet 91. Therefore, a great variation is generated in the projection height h of the surface electrode portion 96 which is formed and the distance W from the peripheral edge of the surface electrode portion 96 to that of the short circuit portion 98, that is, the diameter R.
In the case in which the projection height h of the surface electrode portion 96 has a great variation, it is hard to carry out a stable electrical connection to the circuit device to be inspected. On the other hand, in the case in which the diameter of the surface electrode portion 96 has a great variation, there is a possibility that the adjacent surface electrode portions 96 might be short-circuited.
Therefore, as a means for solving the above described problems, there is means for reducing the projection height h of the surface electrode portion 96 and for reducing the diameter of the surface electrode portion 96 which is thus obtained. That is a means for reducing a diameter r of the short circuit portion 98 (which indicates the smallest length in the case in which a sectional shape is not circular), that is, a diameter of the through hole 98H of the insulating sheet 91 to reduce a diameter of the surface electrode portion 96. In a sheet-like probe obtained by the former means, however, it is hard to reliably achieve a stable electrical connection to the electrode to be inspected.
On the other hand, it is hard to carry out the formation itself of the short circuit portion 98 and the surface electrode portion 96 through the electrolytic plating treatment by the latter means.
In order to solve such problems, there have been proposed sheet-like probes obtained by disposing a large number of electrode structures having a tapered surface electrode portion which has a smaller diameter from a base end toward a tip respectively in Patent Document 5 and Patent Document 6.
The sheet-like probe described in the Patent Document 5 is manufactured in the following manner.
As shown in FIG. 37(a), there is prepared a laminate material 90B obtained by forming a resist film 93A and a surface side metal layer 92A on a surface of an insulating sheet 91 in this order and laminating a back side metal layer 92B on a back face of the insulating sheet 91.
As shown in FIG. 37(b), then, there is formed a through hole communicating with each of the back side metal layer 92B, the insulating sheet 91 and the resist film 93A in the laminate material 90B and extended in a direction of a thickness.
Consequently, a concave portion 90K for forming an electrode structure which has a tapered configuration adapted to a short circuit portion and a surface electrode portion in an electrode structure to be formed is provided on a back face of the laminate material 90B.
As shown in FIG. 37(c), subsequently, a plating treatment is carried out by setting the surface side metal layer 92A in the laminate material 90B to be an electrode so that the concave portion 90K for forming an electrode structure is thus filled with a metal to form a surface electrode portion 96 and a short circuit portion 98.
Then, the back side metal layer 92B in the laminate material is subjected to an etching treatment and is thus removed partially. Consequently, a back electrode portion 97 is formed as shown in FIG. 37(d). Thus, the sheet-like probe 90 is obtained.
Moreover, the sheet-like probe described in the Patent Document 6 is manufactured in the following manner.
As shown in FIG. 38(a), there is prepared a laminate material 90C obtained by forming a surface side metal layer 92A on a surface of an insulating sheet material 91A having a greater thickness than an insulating sheet in a sheet-like probe to be formed and laminating a back side metal layer 92B on a back face of the insulating sheet material 91A.
As shown in FIG. 38(b), then, there is formed a through hole communicating with each of the back side metal layer 92B and the insulating sheet material 91A in the laminate material 90C and extended in a direction of a thickness. Consequently, a concave portion 90K for forming an electrode structure which has a tapered configuration adapted to a short circuit portion and a surface electrode portion in an electrode structure to be formed is provided on a back face of the laminate material 90C.
By carrying out a plating treatment with the surface side metal layer 92A in the laminate material 90C set to be an electrode, subsequently, the concave portion 90K for forming an electrode structure is thus filled with a metal to form a surface electrode portion 96 and a short circuit portion 98 as shown in FIG. 38(c).
Subsequently, the surface side metal layer 92A in the laminate material 90C is removed, and furthermore, the insulating sheet material 91A is subjected to an etching treatment, thereby removing a surface side portion of the insulating sheet. As shown in FIG. 38(d), thus, the insulating sheet material 91 having a predetermined thickness is formed and the surface electrode portion 96 is exposed.
Then, the back side metal layer 92B is subjected to the etching treatment so that the back electrode portion 97 is formed. Thus, the sheet-like probe 90 is obtained as shown in FIG. 38(e).
According to such a sheet-like probe 90, the surface electrode portion 96 is tapered. Therefore, the surface electrode portion 96 having a small diameter and a great projection height can be formed in a state in which a distance from the surface electrode portion 96 of an adjacent electrode structure is maintained sufficiently. Furthermore, each of the surface electrode portions 96 of the electrode structure 95 is formed by setting, as a cavity, the concave portion 90K for forming an electrode structure which is provided on the laminate material. Consequently, it is possible to obtain the electrode structure 95 having a small variation in the projection height of the surface electrode portion 96.
Moreover, as shown in FIG. 39, a plate ring-shaped support plate 99 formed of ceramics, for example, is provided in the peripheral edge portion of the insulating sheet 91 of such a sheet-like probe 90 in order to support the insulating sheet 91 with the rigidity thereof. As shown in FIG. 40, a support plate 99 and the insulating sheet 91 are bonded and fixed by an adhesive 100.    Patent Document 1: Japanese Laid-Open Patent Publication No. 1995-231019    Patent Document 2: Japanese Laid-Open Patent Publication No. 1976-93393    Patent Document 3: Japanese Laid-Open Patent Publication No. 1978-147772    Patent Document 4: Japanese Laid-Open Patent Publication No. 1986-250906    Patent Document 5: Japanese Laid-Open Patent Publication No. 1999-326378    Patent Document 6: Japanese Laid-Open Patent Publication No. 2002-196018    Patent Document 7: Japanese Laid-Open Patent Publication No. 2004-172589